Quantitation of an acetaldehyde adduct in human leukocyte DNA and the effect of smoking cessation
Quantitation of an acetaldehyde adduct in human leukocyte DNA and the effect of smoking cessation
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DOI：
10.1021/tx060232x
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发表时间：
2007-01-01
影响因子：
4.1
通讯作者：
Hecht, Stephen S.
中科院分区：
文献类型：
--
作者：
Chen, Li;Wang, Mingyao;Hecht, Stephen S.
乙醛是香烟烟雾中最常见的致癌物质之一。它也是乙醇的主要代谢物，广泛存在于人类饮食和环境中。乙醛 DNA 加合物对其致癌特性至关重要。乙醛 DNA 加合物在与烟草和酒精暴露相关的人类癌症中的作用可以通过合适的生物标志物进行研究。因此，在本研究中，我们开发了一种分析人类白细胞 DNA 中乙醛主要 DNA 加合物 N-2-亚乙基-dGuo (1) 的方法。在 NaBH3CN 存在下对白细胞 DNA 进行酶水解，将加合物 1 转化为 N-2-乙基-dGuo (2)。 [N-15(5)]N-2-乙基-dGuo用作内标。固相萃取后，通过 LC-ESI-MS/MS-SRM 定量 N-2-乙基-dGuo。该方法灵敏、准确、精密，适用于低微克量的 DNA。它被用来调查戒烟对加合物 1 水平的影响，加合物 1 的测量为加合物 2。25 名轻度饮酒者有资格参加这项研究。加合物 2 的水平在相隔一周的两个基线时间点进行量化，并在戒烟戒酒 4 周后再次量化。吸烟者白细胞中加合物 2 的平均 (+/- S.D.) 水平在两个基线点为 1310 +/- 1720（范围 124-7700）和 1120 +/- 1140（范围 138-5760）fmol/mu mol dGuo，以及 705 +/- 438（范围 111-1530）停药 4 周后 fmol/mu mol dGuo。戒烟后加合物 2 的中位水平显着下降 28% (P = 0.02)。这些结果表明，可以通过 MS/MS 方法可靠地定量人类白细胞 DNA 中的主要乙醛 DNA 加合物，并且吸烟对其水平有适度但显着的影响。
Acetaldehyde is one of the most prevalent carcinogens in cigarette smoke. It is also a major metabolite of ethanol and is found widely in the human diet and environment. Acetaldehyde DNA adducts are critical for its carcinogenic properties. The role of acetaldehyde DNA adducts in human cancer related to tobacco and alcohol exposure could be investigated with a suitable biomarker. Therefore, in this study, we have developed a method for analysis of the major DNA adduct of acetaldehyde, N-2-ethylidene-dGuo (1), in human leukocyte DNA. Leukocyte DNA was subjected to enzyme hydrolysis in the presence of NaBH3CN, which converts adduct 1 to N-2-ethyl-dGuo (2). [N-15(5)]N-2-ethyl-dGuo was used as the internal standard. After solid-phase extraction, N-2-ethyl-dGuo was quantified by LC-ESI-MS/MS-SRM. The method was sensitive, accurate, and precise, and applicable to low microgram amounts of DNA. It was applied to investigate the effect of smoking cessation on levels of adduct 1, measured as adduct 2. Twenty-five smokers who were only light drinkers were eligible for the study. Levels of adduct 2 were quantified at two baseline time points separated by one week and again after four weeks of abstinence from smoking and alcohol consumption. The mean (+/- S.D.) levels of adduct 2 measured in the leukocytes of the smokers were 1310 +/- 1720 (range 124-7700) and 1120 +/- 1140 (range 138-5760) fmol/mu mol dGuo at the two baseline points and 705 +/- 438 (range 111-1530) fmol/mu mol dGuo after 4 weeks of cessation. The median level of adduct 2 decreased significantly by 28% upon quitting smoking (P = 0.02). These results demonstrate that the major acetaldehyde DNA adduct can be reliably quantified by MS/MS methods in human leukocyte DNA and that cigarette smoking has a modest but significant effect on its levels.